Dental drill and method for producing same

ABSTRACT

The invention relates to a method for producing a dental drill that has a shank ( 1 ) and a work section. The shank contains a centrally arranged, continuous first channel ( 3 ). The work section contains one or more continuous, spiral-shaped further channels ( 4   a,    4   b ). The first channel and the further channels open into a common chamber ( 5 ) connecting the shank and the work section. The shank is sintered with the work section in order to form a one-piece, sintered component that encloses the chamber connecting the shank and the work section.

The invention relates to a dental drill and a method for production thereof.

Dental drills of one-piece construction are already known, which include a shank and an adjoining work section having one or more cutting edges, the drill being furnished in the interior of the shank with a central coolant channel. This coolant channel serves, in working operation of the dental drill, for the purpose of transporting a coolant, particularly a cooling liquid, into the region of the work section where it is used for cooling the work section and the currently treated tooth of a patient.

In known dental drills of that kind the said coolant channel opens into the transition region between the shank and the work section so that coolant already issues in the region of the rear end of the work section and thus directly cools merely the rear part of the work section. A disadvantage of drills of that kind is that only inadequate cooling of the cutting region of the dental drill and also inadequate cooling of the currently treated tooth of the patient take place.

A dental drill having a shank and a work section connected with the shank is described in DE 10 2009 043 875.0. The shank includes a centrally arranged, continuous first channel. The work section has one or more continuous, helically extending further channels. Provided between the shank and the work section is a gap into which the first channel and the further channels open. The shank and the work section are connected together by means of clamping sleeve, a soldered connection or an adhesive connection.

The object of the invention consists in indicating a method of producing a dental drill and a dental drill with improved cooling of the cutting region, which drill does not require any additional connecting material in the transition region between the shank and the work section, particularly any clamping sleeve, solder material or also adhesive material.

This object is fulfilled by a method with the features indicated in claim 1 or by a dental drill with the features indicated in claim 5. Advantageous embodiments and developments of the invention are the subject of the dependent claims.

The advantages of the invention consist particularly in that a dental drill is provided which in the transition region between the shank and work section has no visible seam location or joint location. Moreover, no connecting materials are provided in this transition region, such as, for example, solder material, adhesive material or a clamping sleeve. This has the advantage that the bio-compatibility of the dental drill is improved. In this connection it is of significance that a dental drill during tooth treatment has contact with the lips, tongue and teeth of a patient. Due to the non-presence of connecting materials such as a clamping sleeve, solder material or adhesive material it is ensured that no materials harmful to the human organism can be absorbed by way of the mucous membrane of the patient and thereby place the health of the patient at risk. Moreover, in advantageous manner patients who have allergies to the material of the clamping sleeve, solder connection or adhesive connection can be prevented from coming into contact with these materials.

A further advantage of the invention is that creation of sealing problems in the transition region between the shank and the work section is excluded. This is attributable to the fact that through the sintering of the shank with the work section the particles present in the surface region of the shank mix with the particles present in the surface region of the work of the work section in such a manner that a joint-free connection of the shank with the work section arises. Consequently, there are no visible seam locations or joint locations through which cooling liquid could undesirably escape during operation of the dental drill.

Moreover, in the case of a dental drill according to the invention it is ensured that the cooling liquid is guided without pressure loss up to the end region, which is remote from the shank, of the helically extending further channels and issues at that point so that the cutting region of the dental drill and also the treated tooth of the patient are cooled in desired manner.

Further advantageous characteristics of the invention are evident from the exemplifying explanation thereof by way of the figures, in which:

FIG. 1 shows a longitudinal sectional illustration of a dental drill according to a first embodiment of the invention,

FIG. 2 shows a longitudinal sectional illustration of a dental drill according to a second embodiment of the invention,

FIG. 3 shows diagrams for explanation of a method of producing a dental drill according to the invention and

FIG. 4 shows a longitudinal sectional illustration of a dental drill according to a third embodiment of the invention.

Dental drills according to the invention have a shank and a work section, wherein the shank has a centrally arranged, continuous first channel, the work section has one or more continuous, helically extending further channels, the first channel and the further channels open into a common chamber connecting the shank and the work section and the shank and the work section are sintered together. A design of that kind of a dental drill creates the possibility of transporting, during working operation of the dental drill, a sufficient quantity of coolant, particularly cooling liquid, directly to the cutting region of the work section of the dental drill so that cooling, which is improved by comparison with known dental drills, of the cutting region and the currently treated tooth of the patient is achieved.

FIG. 1 shows a diagram of a longitudinal sectional illustration of a dental drill according to a first embodiment of the invention. This dental drill has a cylindrically formed shank 1 and a similarly cylindrically formed work section 2. A continuous first channel 3 extending in axial direction is centrally provided in the shank 1. The diameter of the shank 1 is denoted by d1.

Provided in the work section 2 of the dental drill are two continuous, helically extending further channels 4 a and 4 b which communicate with the cutting region 2 b of the work section 2. The diameter of the work section 2 is denoted by d2 and corresponds with the diameter d1 of the shank 1.

A chamber 5 is provided in the interior of the dental drill in the transition region from shank 1 to work section 2. In the case of the embodiment shown in FIG. 1 this chamber 5 is of disc-shaped construction. Not only the first channel 3, but also the two helical further channels 4 a and 4 b open into the chamber 5, which can alternatively also be constructed to be slot-shaped, cylindrical, polygonal or conical.

In working operation of the dental drill, for example for the preparation of a jawbone for later reception of an implant or for removal of caries from a tooth of a patient a coolant, particularly a cooling liquid, is delivered under low pressure into the first channel 3 from the bottom in FIG. 1. The coolant runs through the rectilinearly formed first channel 3, fills the chamber 5 provided in the transition region from the shank 1 to the work section 2, penetrates from the chamber 5 into the helically extending further channels 4 a and 4 b, runs through these and is then delivered in the cutting region 2 b of the work section 2. Consequently, not only the cutting region forming the work region of the dental drill, but also the currently treated tooth of the patient are directly cooled by the coolant issuing from the channels 4 a and 4 b.

The shank 1 and the work section 2 of the dental drill can consist of the same material or of different materials. The shank 1 preferably consists of steel, ceramic, hard metal or plastic and the work section 2 of steel, ceramic or hard metal. The cutting region 2 b of the work section 2 can consist of the same material as the remaining part of the work section 2 or also of another material.

FIG. 2 shows a diagram of a longitudinal sectional illustration of a dental drill according to a second embodiment of the invention. This dental drill has a cylindrically formed shank 1 and a similarly cylindrically formed work section 2. A continuous first channel 3 extending in axial direction is centrally provided in the shank 1. The diameter of the shank 1 is denoted by d1.

Provided in the work section 2 of the dental drill are two continuous, helically extending further channels 4 a and 4 b communicating with the cutting region 2 b of the work section 2. The diameter of the work region 2 is denoted by 2 and corresponds with the diameter d1 of the shank 1.

A chamber 5 is provided in the interior of the dental drill in the transition region from the shank 1 to the work section 2. In the case of the embodiment shown in FIG. 2 this chamber 5 is constructed to be conical, but can also have a different shape. Not only the first channel 3, but also the two helical further channels 4 a and 4 b open into the chamber 5. In the illustrated embodiment the chamber 5 is provided in the shank 1. Alternatively thereto it can also be provided in the work section 2. A further alternative consists in providing a part of the chamber in the shank 1 and the other part of the chamber in the work section 2.

In working operation of the dental drill, for example for removal of caries from a tooth of a patient, a coolant, particularly a cooling liquid, is introduced under pressure into the first channel 3 from the bottom in FIG. 2. The coolant runs through the rectilinearly formed first channel 3, fills the chamber 5 provided between the shank 1 and the work section 2, penetrates from the chamber 5 into the helically extending further channels 4 a and 4 b, runs through these and is then issued in the cutting region 2 b of the work section 2. Consequently, not only the cutting region, which forms the work region of the dental drill, but also the currently treated tooth of the patient are directly cooled by the coolant issuing from the channels 4 a and 4 b.

The shank 1 and the work section 2 of the dental drill can consist of the same material or of different materials. Preferably, the shank 1 consists of steel, ceramic, hard metal or plastic and the work section 2 of steel, ceramic or hard metal. The cutting region 2 b of the work section 2 can consist of the same material as the remaining part of the work section 2 or also of a different material.

FIG. 3 shows diagrams for explanation of a method of producing a dental drill according to the invention. In that case, production of the dental drill shown in FIG. 1 is explained on the basis of FIGS. 3 a and 3 b and production of the dental drill shown in FIG. 2 is explained on the basis of FIGS. 3 c and 3 d.

For production of the dental drill shown in FIG. 1 initially a shank 1 and a work section 2 are produced independently of one another. The shank 1 is shown in FIG. 3 b. The work section 2 is illustrated in FIG. 3 a.

For production of the shank 1, plastic material is extruded by a first extrusion tool in such a manner that a first body, which consists of plastic material, with a centrally arranged, continuous first channel issues from the first extrusion tool. The first body issued from the first extrusion tool is of cylindrical construction and has a diameter d1. The body issued from the first extrusion tool is cut to a predetermined length l1 and then dried so that its consistency solidifies.

For production of the work section 2, plastic material is extruded by a second extrusion tool in such a manner that a second body, which consists of plastic material, with rectilinearly extending further channels issues from the second extrusion tool. The body issued from the second extrusion tool is similarly of cylindrical construction. It has a diameter d2 which corresponds with the diameter d1 of the shank. The second body issued from the second extrusion tool is cut to a predetermined second length l2. The cut-to-length second body is subjected to a uniform twisting of a rolling motion, the speed of which constantly changes over the entire length l2, by means of a friction surface arrangement while being supported over its entire length. Helically extending further channels 4 a and 4 b, as illustrated in FIG. 3 a, are thereby formed from the initially rectilinearly extending further channels. The body produced in this manner is dried so that its consistency solidifies. The chamber 5, which in the illustrated embodiment is of rectangular form, is ground into the rear region of the dried body. The cutting region 2 b is similarly formed in the front region of the dried body by means of a grinding process.

Thereafter—as is illustrated between FIGS. 3 a and 3 b by the arrows x—the bodies solidified by drying are placed against one another in axial direction and heated. This hearing is carried out in such a manner that the mutually adjoining surfaces of the heated bodies melt and that the mutually adjoining surfaces are sintered together in such a manner that after connection thereof no seam locations or joint locations are visible. The sintered-together bodies are subsequently dried again so that the consistency thereof further solidifies.

A one-piece sintered component, which completely encloses the chamber 5 connecting the shank 1 and the work section 2, is formed by the afore-described sintering of the shank to the work section. Consequently, the transition region between the shank and the work section is free of additional connecting materials of any kind.

For producing the dental drill shown in FIG. 2 initially a shank 1 and a work section 2 are produced independently of one another. The shank 1 is shown in FIG. 3 d. The work section 2 is illustrated in FIG. 3 c.

For production of the shank 1, plastic material is extruded by a first extrusion tool in such a manner that a first body, which consists of plastic material, with a centrally arranged, continuous first channel 3 issues from the first extrusion tool. The first body issued from the first extrusion tool is of cylindrical construction and has a diameter d1. The body issued from the first extrusion tool is cut to a predetermined length l3 and then dried so that the consistency thereof solidifies. The chamber 5, which in the illustrated embodiment is of conical construction, is ground into the front region of the dried body.

For production of the work section 2, plastic material is extruded by a second extrusion tool in such a manner that a second body, which consists of plastic material, with rectilinearly extending further channels issues from the second extrusion tool. The body issued from the second extrusion tool is similarly of cylindrical construction. It has a diameter d2, which corresponds with the diameter d1 of the shank. The second body issued from the second extrusion tool is cut to a predetermined second length l4. The cut-to-length second body is subjected to a uniform twisting of a rolling motion, the speed of which constantly changes over the entire length l4, by means of a friction surface arrangement while being supported over its entire length. Helically extending further channels 4 a and 4 b, as illustrated in FIG. 3 c, are thereby formed from the initially rectilinearly extending further channels. The body produced in this manner is dried so that the consistency thereof solidifies. The cutting region 2 b is formed in the front region of the dried body by means of a grinding process.

Thereafter—as illustrated between the FIGS. 3 d and 3 c by the arrows x—the bodies solidified by drying are placed against one another in axial direction and heated. This heating is carried out in such a manner that the mutually adjoining surfaces of the heated bodies melt and that the mutually adjoining surfaces are sintered together in such a manner that after connection thereof no seam locations or joint locations are visible. The bodies sintered together are subsequently dried again so that the consistency thereof further solidifies.

A one-piece sintered component, which completely encloses the chamber 5 connecting the shank 1 and the work section 2, is formed by the afore-described sintering of the shank to the work section. Consequently, the transition region between the shank and the work section is free of additional connecting materials of any kind.

FIG. 4 shows a longitudinal sectional illustration of a dental drill according to a third embodiment of the invention. In this third embodiment the chamber 5 provided in the transition region from the shank 1 to the work section 2 is of slot-shaped construction. The width of the chamber 5 in the radial direction of the dental drill is matched to the radial external dimensions of the helically extending channels 4 a and 4 b so that the chamber 5 does not protrude in radial direction outwardly beyond the helically extending channels. This is also apparent from the illustration on the righthand side of FIG. 4, wherein this illustration shows a cross-sectional illustration of the dental drill along the section line S shown by a dot-dashed line on the lefthand side of FIG. 4.

In the case of the afore-described embodiments the shank in each instance has a centrally arranged central channel. According to a modified form of embodiment a dental drill can also be constructed in such a manner that the helically extending channels provided in the work region extend as far as the shank and also run completely through the shank. In this case the feed of coolant is provided into the grip member, which is not illustrated in the figures, of the dental drill.

A chamber can, by way of example, similarly be provided there, through which chamber the cooling liquid supplied from a cooling liquid source is conducted onward in the helically extending channels of the dental drill.

REFERENCE NUMERAL LIST

-   1 shank -   2 work section -   2 b cutting region of the work section -   3 first channel -   4 a, 4 b further channels -   5 chamber -   d1 diameter of the shank -   d2 diameter of the work section -   l1, l3 length of the shank -   l2, l4 length of the work section 

1. Method of producing a dental drill having a shank and a work section, wherein the shank has a centrally arranged, continuous first channel and the work section has one or more continuous, helically extending further channels, the first channel and the further channels opening into a common chamber connecting the shank and the work section, comprising _(t)he following steps: producing the shank having a centrally arranged, continuous first channel, producing the work section having one or more continuous, helically extending further channels and sintering the shank to the work section to form a one-piece, sintered component which encloses the chamber connecting the shank and the work section.
 2. Method according to claim 1, wherein for producing the shank a plastic material is extruded by a first extrusion tool in order to provide a first body, which consists of plastic material, with a centrally arranged, continuous first channel, the body leaving the first extrusion tool is cut to a predetermined first length and the cut-to-length body is hardened by drying.
 3. Method according to claim 1, wherein for producing the work section a plastic material is extruded by a second extrusion tool in order to provide a second body, which consists of plastic material, with rectilinearly extending further channels, the second body leaving the second extrusion tool is cut to a predetermined second length, the cut-to-length second body is subjected to a uniform twisting of a rolling motion, the speed of which changes linearly and constantly over the entire length, by means of a friction surface arrangement while being supported over its entire length, and the twisted body is hardened by drying.
 4. Method according to claim 2, wherein the bodies hardened by drying are placed against one another in axial direction and the bodies placed against one another are heated in such a manner that the mutually adjoining surfaces thereof are melted so that the mutually adjoining surfaces are sintered together.
 5. Dental drill with a shank (1) and a work section (2), wherein the shank has a centrally arranged, continuous first channel (3), the work section has one or more continuous, helically extending further channels (4 a, 4 b), a chamber (5) is provided between the shank and work section, the first channel and the further channels open into the chamber and the shank and the work section form a one-piece component which is connected by sintering and which completely encloses the chamber (5) connecting the shank (1) and the work section (2).
 6. Dental drill according to claim 5, wherein the end region, which is remote from the shank (1), of the helically extending further channels (4 a, 4 b) respectively communicates with the cut region (2 b) of the work section (2).
 7. Dental drill according to claim 5, wherein the chamber (5) is formed to be disc-shaped or slot-shaped,
 8. Dental drill according to claim 5, wherein the chamber (5) is formed to be polygonal or cylindrical.
 9. Dental drill according to claim 5, wherein the chamber (5) is formed to be conical. 